Intraocular lens and method of forming the lens

ABSTRACT

An intraocular lens formed of a soft, resilient polymeric optical element and a resilient polymeric support having an annular portion embedded in the optical element and a pair of mounting arms extending outwardly of the optical element. The optical element and support can be folded for insertion into the eye via a small incision. The support is embedded in the optical element during molding and polymerization of the optical element.

FIELD OF THE INVENTION

The invention relates to intraocular lenses. The lens comprises a soft,resilient polymeric optical element and a resilient polymeric supportembedded therein and having outwardly extending mounting arms. Thesupport is embedded in the optical element during molding of the opticalelement.

BACKGROUND OF THE INVENTION

Artificial intraocular lenses, used to replace damaged or diseasednatural lenses in the eye, have been widely used in the last severalyears. Typically, such artificial intraocular lenses comprise some typeof optical element and a support coupled to the element for positioningthe optical element in the proper location in the eye.

These lenses have typically included hard polymeric or glass opticalelements with metallic or polymeric supports. One problem with hardlenses is that the incision in the eye to insert them must be at leastas large as the diameter of the optical portion of the lens. Thus, thepatient must experience a fairly traumatic large incision.

Use of soft, foldable polymeric lenses is hampered because it isdifficult to support them and it is difficult to insert them into theeye.

Another problem involving either hard or soft intraocular lenses is theneed for adhesives or extra, complicated steps to connect the supportsto the optical element.

Thus, there is a continuing need for improvement in intraocular lenses.

Examples of such prior art intraocular lenses are disclosed in thefollowing U.S. patents: U.S. Pat. Nos. 2,834,023 to Lieb; 4,159,546 toShearing; 4,172,297 to Schlegel; 4,206,518 to Jardon et al; 4,242,760 toRainin; 4,253,200 to Kelman; 4,257,130 to Bayers; and 4,363,143 toCallahan.

SUMMARY OF THE INVENTION

Accordingly, a primary object of the invention is to provide anintraocular lens having a soft, resilient optical element and aresilient support, both of which are foldable for easy insertion intothe eye via a small incision, and having a support more rigid than theoptical element to ease insertion and to prevent collapse or distortionof the optical element after insertion into the eye.

Another object of the invention is to provide such an intraocular lensthat avoids the use of adhesives or numerous steps to couple a supportto the optical element.

Another object of the invention is to provide an intraocular lens thatis comprised of a soft, resilient polymeric optical element and aresilient polymeric support embedded therein during molding of theoptical element.

The foregoing objects are basically attained by providing a method ofmaking an intraocular lens comprising the steps of forming a resilientsupport including an annular portion and mounting arms, positioning aportion of the support in a mold, molding an optical element in the moldincluding introducing material forming the optical element into the moldin liquid form and surrounding the portion of the support in the moldwith such material forming the optical element, converting the materialforming the optical element from liquid form into solid form, andremoving the intraocular lens formed by the support and the opticalelement from the mold.

The foregoing objects are also attained by providing an intraocular lenscomprising a resilient optical element; and a resilient support havingan annular portion and mounting arms, the annular portion being embeddedin and surrounded by the material forming the optical element, themounting arms extending outwardly of the material forming the opticalelement.

Other objects, advantages and salient features of the present inventionwill become apparent from the following detailed description, which,taken in conjunction with the annexed drawings, discloses a preferredembodiment of the present invention.

DRAWINGS

Referring now to the drawings which form a part of this originaldisclosure:

FIG. 1 is a top plan view of the intraocular lens in accordance with theinvention including an optical element and a support embedded therein;

FIG. 2 is a top plan view of the support for the optical elementincluding an annular portion and a pair of mounting arms, without theoptical element coupled thereto;

FIG. 3 is an enlarged right side elevational view in section of theintraocular lens in accordance with the invention taken along line 3--3in FIG. 1;

FIG. 4 is a front elevational view in section taken along line 4--4 inFIG. 1 showing a portion of the support embedded in and surrounded bythe optical element;

FIG. 5 is a side elevational view, in partial section, of the supporthaving a portion located in a mold and the optical element surroundingthat portion of the support in the mold; and

FIG. 6 is a top elevational view in section taken along line 6--6 ofFIG. 5 showing the bottom half of the mold as well as the opticalelement and the support.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1-4, the intraocular lens 10 in accordance withthe invention comprises a soft transparent optical element 12 and asupport 14, both of which are flexible and resilient, and thereforebendable or foldable. As seen in FIGS. 3 and 4, a portion of the supportis embedded in and surrounded by the optical element. This isaccomplished by inserting a portion of the support in a mold and moldingthe optical element around that portion of the support, as seen in FIGS.5 and 6. The support is more rigid than the optical element to providethe necessary structural suspension of the optical element when placedin the eye.

The support 14 comprises an annular portion 16 and a pair of curvedmounting arms 18 and 20 rigidly coupled thereto and extending initiallysubstantially tangentially thereof on diametrically opposed sides. Thearms and annular portion are coplanar, although the tips of the arms canbe bent out of the plane of the arms and annular portion to provide forbetter connection in the eye. Advantageously, the support is about 13millimeters long and the annular portion 16 is about 5.5 millimeters indiameter. In cross section, the support material is circular. Thethickness of the material forming the annular portion and mounting armsis preferably uniform and advantageously about 0.2 to 0.3 millimeters indiameter.

As seen in FIGS. 1-4, the support 14 is a one-piece molded member;although it is possible to form the support member by rigidly attaching,in a suitable manner such as by adhesives or fusion, the mounting armsto the annular portion. Advantageously, the entire support is formedfrom polymeric material such as tetrafluoroethylene. Alternatively, thesupport could be formed of metal such as stainless steel.

Since the optical element is made of soft polymeric material andtherefore cannot support itself, the support is advantageously morerigid than the optical element, yet flexible and bendable. The meltingpoint of the material forming the support is higher than the elevatedtemperatures used to polymerize the material forming the opticalelement, as will be described hereinafter.

The optical element 12, as best seen in FIGS. 1 and 3-4, is circular inplan view, is transparent and comprises a first surface 22 and a secondsurface 24, each of which is convex. The optical element isadvantageously molded as one piece onto and around the annular portion16 and part of the mounting arms 18 and 20 so that such a portion of thesupport is surrounded by and embedded in the material forming theoptical element.

Advantageously, the optical element is formed from a monomer formulationresulting in a silicone elastomer upon polymerization. Examples of suchmonomers are: hexamethyl-cyclotrisiloxane,octamethyl-cyclotetrasiloxane, decamethyl-cyclopentasiloxane,octaphenylcyclo-tetrasiloxane, diphenylsilane-diol,trimethyltriphenyl-cyclotrisiloxane, vinylmethyl-cyclosiloxanes,trifluoropropylmethyl-cyclosiloxanes, methylhydro-cyclosiloxane,hexamethyl-disiloxane, divinyltetra-methyldisiloxane andtetramethyl-disiloxane. Polymerization takes places for one to two hoursat a temperature of 60°-200° C.

As seen in FIGS. 3 and 4, the support 14 is essentially centrallylocated in the optical element 12 equidistant from the first and secondconvex surfaces 22 and 24 and equally radially spaced from the outerperiphery of the optical element.

As seen in FIGS. 5 and 6, a mold 26 is used to form the intraocular lens10 and comprises an upper part 28 with an upper concave cavity 30 and alower part 32 with a lower concave cavity 34. The upper and lower partsof the mold are relatively movable towards and away from each other inorder to insert the support therein, introduce material forming theoptical element therein, and remove the combined optical element andsupport once the intraocular lens is fully formed. As seen in FIG. 6,the lower part 32 of the mold has a pair of slots 36 and 38, which aresemi-cylindrical in cross section, for the reception of the mountingarms in the support. Similar slots, not shown, are also found in theupper part of the mold.

Thus, in forming the intraocular lens 10 in accordance with theinvention, the mold parts are opened, and then the support 14 ispositioned in the mold so that the annular portion 16 and part of thearms are located in the lower cavity 34 as seen in FIG. 6.

Then, a monomer formulation in liquid form, having a volume somewhatgreater than that of the two cavities, is introduced into the lower moldcavity and the mold is closed with the excess volume leaking out betweenthe mold parts. The mold is then heated for a predetermined time at anelevated predetermined temperature that will polymerize the monomerslocated therein into a solid polymer. As seen in FIGS. 5 and 6, when thematerial in liquid form is introduced into the mold, it surrounds theportion of the support located therein so that the support is ultimatelyembedded therein after polymerization.

Following polymerization of the optical element material, the mold isopened and the combined optical element and support are removedtherefrom.

Rather than introducing the liquid monomers into an open mold and thenclosing the mold, the mold can be closed after insertion of the supportand the monomers then can be injected into the mold under pressure via asuitable input port. Polymerization as described above then takes place.

As an alternative to silicone polymer, a hydrogel polymer can be used toform the optical element. This material is very hard when dry andbecomes soft after it is hydrated. When this material is used, the moldneed only encase the support in a block of the hydrogel polymer and,after removal from the mold, the block can be lathe cut to a preciseoptical shape.

While one advantageous embodiment has been chosen to illustrate theinvention, it will be understood by those skilled in the art thatvarious changes and modifications can be made therein without departingfrom the scope of the invention as defined in the appended claims.

What is claimed is:
 1. An intraocular lens, the combination comprising:asoft, resilient optical element; and a resilient support having anannular portion and mounting arms, said annular portion being completelyembedded in and completely surrounded by the material forming saidoptical element, said mounting arms being coupled to said annularportion and extending outwardly of the material forming said opticalelement.
 2. An intraocular lens according to claim 1, whereinsaidsupport is integrally formed as one piece.
 3. An intraocular lensaccording to claim 1, whereinsaid support is formed of polymericmaterial.
 4. An intraocular lens according to claim 3, whereinsaidpolymeric material is tetrafluoroethylene.
 5. An intraocular lensaccording to claim 1, whereinsaid optical element is formed of polymericmaterial.
 6. An intraocular lens according to claim 1, whereinsaidoptical element is formed of silicone.
 7. An intraocular lens accordingto claim 1, whereinsaid optical element is formed of polymeric material,and said support is formed of polymeric material.
 8. An intraocular lensaccording to claim 1, whereineach of said mounting arms has a portionextending substantially tangentially of said annular portion.
 9. Anintraocular lens according to claim 8, whereinsaid annular portion andsaid mounting arms lie substantially in the same plane.
 10. Anintraocular lens according to claim 1, whereinsaid annular portion andsaid mounting arms lie substantially in the same plane.